Vertical navigation is a tool that can reduce pilot work load and fatigue and thus improve flight safety, especially in a high work load procedure such as an instrument approach in the presence of severe weather. Vertical navigation is typically offered in low end systems in the form of a pitch attitude hold mode, or vertical rate mode or altitude select mode. Some autopilots offer an altitude limit alert. High end integrated systems, often termed Electronic Flight Information Systems (EFIS) may offer a vertical navigation feature between GPS waypoints as programmed into the EFIS. EFIS systems may combine GPS, heading and attitude gyro information, altimeter, and autopilot control in one large integrated computer screen display, often referred to as a “glass” display. EFIS systems can be quite expensive, out of the range of typical budgets for smaller aircraft. Thus, there is a need for improved vertical navigation capability in economical forms available to smaller aircraft.